Optomechanical Design and Application of Solar-Skylight Spectroradiometer

Using a solar radiometer is an effective approach for improving the remote sensing of solar irradiance distribution and atmospheric composition. Long-term development of a solar scanning radiometer enables frequent and reliable measurement of atmospheric parameters such as the water vapor column and aerosol optical properties. However, the discrete wavelength radiometer has encountered a bottleneck with respect to its insufficient spectral resolution and limited observation waveband, and it has been unable to satisfy the needs of refined and intelligent on-site experiments. This study proposes a solar-skylight spectroradiometer for obtaining visible and near-IR fine spectrum with two types of measurement: direct-sun irradiance and diffuse-sky radiance. The instrument adopts distributed control architecture composed of the ARM-Linux embedded platform and sensor networks. The detailed design of the measuring light-path, two-axis turntable, and master control system will be addressed in this study. To determine all coefficients needed to convert instrument outputs to physical quantities, integrating sphere and Langley extrapolation methods are introduced for diffuse-sky and direct-sun calibration, respectively. Finally, the agreement of experimental results between spectroradiometers and measuring benchmarks (DTF sun-photometer, microwave radiometer, and Combined Atmospheric Radiative Transfer simulation) verifies the feasibility of the spectroradiometer system, and the radiation information of feature wavelengths can be used to retrieve the characteristics of atmospheric optics.

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Validation and Trend Analysis of Stratospheric Ozone Data from Ground-Based Observations at Lauder, New Zealand

Remote Sensing ◽

10.3390/rs13010109 ◽

2020 ◽

Vol 13 (1) ◽

pp. 109

Author(s):

Leonie Bernet ◽

Ian Boyd ◽

Gerald Nedoluha ◽

Richard Querel ◽

Daan Swart ◽

...

Keyword(s):

New Zealand ◽

Stratospheric Ozone ◽

Microwave Radiometer ◽

Detailed Comparison ◽

Reanalysis Data ◽

Montreal Protocol ◽

Atmospheric Composition ◽

Ozone Trends ◽

Institute Of Technology

Changes in stratospheric ozone have to be assessed continuously to evaluate the effectiveness of the Montreal Protocol. In the southern hemisphere, few ground-based observational datasets exist, making measurements at the Network for the Detection of Atmospheric Composition Change (NDACC) station at Lauder, New Zealand invaluable. Investigating these datasets in detail is essential to derive realistic ozone trends. We compared lidar data and microwave radiometer data with collocated Aura Microwave Limb sounder (MLS) satellite data and ERA5 reanalysis data. The detailed comparison makes it possible to assess inhomogeneities in the data. We find good agreement between the datasets but also some possible biases, especially in the ERA5 data. The data uncertainties and the inhomogeneities were then considered when deriving trends. Using two regression models from the Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS) project and from the Karlsruhe Institute of Technology (KIT), we estimated resulting ozone trends. Further, we assessed how trends are affected by data uncertainties and inhomogeneities. We find positive ozone trends throughout the stratosphere between 0% and 5% per decade and show that considering data uncertainties and inhomogeneities in the regression affects the resulting trends.

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Trend analysis of the 20 years time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-16371-2015 ◽

2015 ◽

Vol 15 (12) ◽

pp. 16371-16400

Author(s):

L. Moreira ◽

K. Hocke ◽

E. Eckert ◽

T. von Clarmann ◽

N. Kämpfer

Keyword(s):

Time Series ◽

Trend Analysis ◽

Southern Oscillation ◽

Stratospheric Ozone ◽

Microwave Radiometer ◽

Atmospheric Composition ◽

Quasi Biennial Oscillation ◽

Ozone Trend ◽

Long Term Trend

Abstract. The ozone radiometer GROMOS (GROund-based Millimeterwave Ozone Spectrometer) performs continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland. GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a Fast-Fourier-Transform spectrometer (FFTS) has been added as backend to GROMOS. The new FFTS and the original FB measured in parallel for over two years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from more than 20 years of stratospheric ozone observations at Bern. The trend analysis has been performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño–Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade-1 at 4.36 hPa, covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of −3.94 % decade-1 at 0.2 hPa.

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Trend analysis of the 20-year time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-10999-2015 ◽

2015 ◽

Vol 15 (19) ◽

pp. 10999-11009 ◽

Cited By ~ 13

Author(s):

L. Moreira ◽

K. Hocke ◽

E. Eckert ◽

T. von Clarmann ◽

N. Kämpfer

Keyword(s):

Time Series ◽

Trend Analysis ◽

Southern Oscillation ◽

Stratospheric Ozone ◽

Microwave Radiometer ◽

Atmospheric Composition ◽

Quasi Biennial Oscillation ◽

Ozone Trend ◽

Long Term Trend

Abstract. The ozone radiometer GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has been performing continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland (46.95° N, 7.44° E, 577 m). GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a fast Fourier transform spectrometer (FFTS) was added as a back end to GROMOS. The new FFTS and the original FB measured in parallel for over 2 years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from stratospheric ozone observations at Bern. The trend analysis was performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño–Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade−1 at 4.36 hPa (37.76 km), covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of −3.94 % decade−1 at 0.2 hPa (59 km).

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Traceability of Long-Term Atmospheric Composition Observations across Global Monitoring Networks: Chemical Metrology Applied to the Measurements of Constituents in Air, Water, and Soil

CHIMIA International Journal for Chemistry ◽

10.2533/chimia.2009.657 ◽

2009 ◽

Vol 63 (10) ◽

pp. 657-660 ◽

Cited By ~ 11

Author(s):

Brigitte Buchmann ◽

Jörg Klausen ◽

Christoph Zellweger

Keyword(s):

Atmospheric Composition ◽

Monitoring Networks ◽

Chemical Metrology

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Comparison of ozone profiles and influences from the tertiary ozone maximum in the night-to-day ratio above Switzerland

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-10259-2017 ◽

2017 ◽

Vol 17 (17) ◽

pp. 10259-10268 ◽

Cited By ~ 2

Author(s):

Lorena Moreira ◽

Klemens Hocke ◽

Niklaus Kämpfer

Keyword(s):

Annual Variation ◽

Lower Stratosphere ◽

Microwave Radiometer ◽

Relative Difference ◽

Atmospheric Composition ◽

Composition Change ◽

Ozone Maximum ◽

Ozone Profile ◽

Mesospheric Ozone ◽

The Mean

Abstract. Stratospheric and middle-mesospheric ozone profiles above Bern, Switzerland (46.95° N, 7.44° E; 577 m) have been continually measured by the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer since 1994. GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). A new version of the ozone profile retrievals has been developed with the aim of improving the altitude range of retrieval profiles. GROMOS profiles from this new retrieval version have been compared to coincident ozone profiles obtained by the satellite limb sounder Aura Microwave Limb Sounder (MLS). The study covers the stratosphere and middle mesosphere from 50 to 0.05 hPa (from 21 to 70 km) and extends over the period from July 2009 to November 2016, which results in more than 2800 coincident profiles available for the comparison. On average, GROMOS and MLS comparisons show agreement generally over 20 % in the lower stratosphere and within 2 % in the middle and upper stratosphere for both daytime and nighttime, whereas in the mesosphere the mean relative difference is below 40 % during the daytime and below 15 % during the nighttime. In addition, we have observed the annual variation in nighttime ozone in the middle mesosphere, at 0.05 hPa (70 km), characterized by the enhancement of ozone during wintertime for both ground-based and space-based measurements. This behaviour is related to the middle-mesospheric maximum in ozone (MMM).

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Changes to the chemical state of the northern hemisphere atmosphere during the second half of the twentieth century

10.5194/acp-2016-927 ◽

2016 ◽

Author(s):

Mike J. Newland ◽

Patricia Martinerie ◽

Emmanuel Witrant ◽

Detlev Helmig ◽

David R. Worton ◽

...

Keyword(s):

Northern Hemisphere ◽

Large Scale ◽

Atmospheric Composition ◽

The Arctic ◽

Major Influence ◽

Secondary Products ◽

Alkyl Nitrates ◽

Mixing Ratios ◽

Wide Range

Abstract. The NOX (NO and NO2) and HOX (OH and HO2) budgets of the atmosphere exert a major influence on atmospheric composition, controlling removal of primary pollutants and formation of a wide range of secondary products, including ozone, that can influence human health and climate. However, there remain large uncertainties in the changes to these budgets over recent decades. Due to their short atmospheric lifetimes, NOX and HOX are highly variable in space and time, and so the measurements of these species are of very limited value for examining long term, large scale changes to their budgets. Here, we take an alternative approach by examining long-term atmospheric trends of alkyl nitrates, the formation of which is dependent on the atmospheric NO / HO2 ratio. We derive long term trends in the alkyl nitrates from measurements in firn air from the NEEM site, Greenland. Their mixing ratios increased by a factor of 4–5 between the 1970s and 1990s. This was followed by a steep decline to the sampling date of 2008. Moreover, we examine how the trends in the alkyl nitrates compare to similarly derived trends in their parent alkanes (i.e. the alkanes which, when oxidised in the presence of NOX, lead to the formation of the alkyl nitrates). The ratios of the alkyl nitrates to their parent alkanes increase from around 1970 to the late 1990's consistent with large changes to the [NO] / [HO2] ratio in the northern hemisphere atmosphere during this period. These could represent historic changes to NOX sources and sinks. Alternatively, they could represent changes to concentrations of the hydroxyl radical, OH, or to the transport time of the air masses from source regions to the Arctic.

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Mineral protection regulates the long-term global preservation of natural organic carbon

10.5194/egusphere-egu21-627 ◽

2021 ◽

Author(s):

Jordon Hemingway ◽

Daniel Rothman ◽

Katherine Grant ◽

Sarah Rosengard ◽

Timothy Eglinton ◽

...

Keyword(s):

Organic Carbon ◽

Redox State ◽

Global Climate ◽

Atmospheric Oxygen ◽

Atmospheric Composition ◽

Earth Surface ◽

Mountain Ranges ◽

Surface Redox ◽

Carbon Erosion

The vast majority of organic carbon (OC) produced by life is respired back to carbon dioxide (CO2), but roughly 0.1% escapes and is preserved over geologic timescales. By sequestering reduced carbon from Earth&#8217;s surface, this &#8220;slow OC leak&#8221; contributes to CO2 removal and promotes the accumulation of atmospheric oxygen and oxidized minerals. Countering this, OC contained within sedimentary rocks is oxidized during exhumation and erosion of mountain ranges. By respiring previously sequestered reduced carbon, erosion consumes atmospheric oxygen and produces CO2. The balance between these two processes&#8212;preservation and respiration&#8212;regulates atmospheric composition, Earth-surface redox state, and global climate. Despite this importance, the governing mechanisms remain poorly constrained. To provide new insight, we developed a method that investigates OC composition using bond-strength distributions coupled with radiocarbon ages. Here I highlight a suite of recent results using this approach, and I show that biospheric OC interacts with particles and becomes physiochemically protected during aging, thus promoting preservation. I will discuss how this mechanistic framework can help elucidate why OC preservation&#8212;and thus atmospheric composition, Earth-surface redox state, and climate&#8212;has varied throughout Earth history.

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Reaching a few 10-15 long-term stability of integrating sphere cold atom clock

Chinese Optics Letters ◽

10.3788/col201816.070201 ◽

2018 ◽

Vol 16 (7) ◽

pp. 070201 ◽

Cited By ~ 1

Author(s):

Yaning Wang Yaning Wang ◽

Yanling Meng Yanling Meng ◽

Jinyin Wan Jinyin Wan ◽

Ling Xiao Ling Xiao ◽

Mingyuan Yu Mingyuan Yu ◽

...

Keyword(s):

Cold Atom ◽

Integrating Sphere ◽

Term Stability ◽

Long Term Stability

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Geosystemics View of Earthquakes

Entropy ◽

10.3390/e21040412 ◽

2019 ◽

Vol 21 (4) ◽

pp. 412 ◽

Cited By ~ 6

Author(s):

Angelo De Santis ◽

Cristoforo Abbattista ◽

Lucilla Alfonsi ◽

Leonardo Amoruso ◽

Saioa A. Campuzano ◽

...

Keyword(s):

Solid Earth ◽

Point Of View ◽

Satellite Observations ◽

Earth System ◽

Seismic Sequences ◽

The Earth ◽

Earth’S Interior ◽

Earth's Interior ◽

Physical Quantities

Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to study the Earth system as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth’s interior to the above atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main objective is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that will be introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth’s interior but also the coupling of the solid earth with the above neutral or ionized atmosphere, and finally culminating with the main rupture along the fault of concern. Particular emphasis will be given to some Italian seismic sequences.

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